A typical motor controller controls driving of a motor by converting AC utility power into DC power and then converting the DC power into AC power with a prescribed voltage using an inverter.
That is, a conventional motor controller detects a current flowing through the motor by a current sensor mounted inside or outside the motor and controls Ons/Offs of switching elements included in an inverter based on the detected current.
In general, the switching elements included in the inverter are driven by a PWM (Pulse Width Modulation) type switching control signal, and the operations of the motor are controlled to evaluate a target frequency.
Meanwhile, there is also a method of controlling a motor by evaluating a current flowing through the motor in a sensor-less manner in order to save costs.
However, the sensor-less type motor control method fails to provide a specific way to protect the motor upon occurrence of some errors on the motor.